--- /dev/null
+<?php
+
+namespace Drupal\Tests\block\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+use Drupal\block\Entity\Block;
+
+/**
+ * Tests that an active block assigned to a non-existing region triggers the
+ * warning message and is disabled.
+ *
+ * @group block
+ */
+class BlockInvalidRegionTest extends BrowserTestBase {
+
+ /**
+ * Modules to install.
+ *
+ * @var array
+ */
+ public static $modules = ['block', 'block_test'];
+
+ protected function setUp() {
+ parent::setUp();
+ // Create an admin user.
+ $admin_user = $this->drupalCreateUser([
+ 'administer site configuration',
+ 'access administration pages',
+ 'administer blocks',
+ ]);
+ $this->drupalLogin($admin_user);
+ }
+
+ /**
+ * Tests that blocks assigned to invalid regions work correctly.
+ */
+ public function testBlockInInvalidRegion() {
+ // Enable a test block and place it in an invalid region.
+ $block = $this->drupalPlaceBlock('test_html');
+ \Drupal::configFactory()->getEditable('block.block.' . $block->id())->set('region', 'invalid_region')->save();
+ $block = Block::load($block->id());
+
+ $warning_message = t('The block %info was assigned to the invalid region %region and has been disabled.', ['%info' => $block->id(), '%region' => 'invalid_region']);
+
+ // Clearing the cache should disable the test block placed in the invalid region.
+ $this->drupalPostForm('admin/config/development/performance', [], 'Clear all caches');
+ $this->assertRaw($warning_message, 'Enabled block was in the invalid region and has been disabled.');
+
+ // Clear the cache to check if the warning message is not triggered.
+ $this->drupalPostForm('admin/config/development/performance', [], 'Clear all caches');
+ $this->assertNoRaw($warning_message, 'Disabled block in the invalid region will not trigger the warning.');
+
+ // Place disabled test block in the invalid region of the default theme.
+ \Drupal::configFactory()->getEditable('block.block.' . $block->id())->set('region', 'invalid_region')->save();
+ $block = Block::load($block->id());
+
+ // Clear the cache to check if the warning message is not triggered.
+ $this->drupalPostForm('admin/config/development/performance', [], 'Clear all caches');
+ $this->assertNoRaw($warning_message, 'Disabled block in the invalid region will not trigger the warning.');
+ }
+
+}